Apparatus for drying paper in a continuous web



W. WHITING Dec. 1o, 192.5.

APPARATUS FOR DRYING PAPER IN A CONTINUOUS WEB Filed May 11, 1934|||l||||||||||||||lll| ||||11 1W festoon. These fe'xpedients have notproved satis- T GFFICE FOR DRYING PPER IN A` 1 CONTINUOUS WEB WilliamlWhiting, no1yoko, Mass., assignor to Whitingv Paper Company, Holyoke,Mass., a corporation of Massachusetts Application Moy 11, 1934, seriaiNo. '125,218

2 claims. 'Ihlsinvention relates to apparatus for -drying paper' in acontinuous web. Loft dried paper has a number di' advantages inappearance and quality andmany attempts have been made to secure similarlaltipearance and 7quality by continuous methodsan'd machines. In onecommon arrangenient the web is carried successivelyaround a series ofsteam heated drumsand according to another me'thod the web ls formedinto a traveling factory in securing results equivalent to loft drying.In the case ofheated drums the shrinking of thepapor about the-umm setop strains which are detrimental to the quality and appearance and inthe festoon method uniform drying conditions Aare difficult ifnot'impossible to obtain since ex'- cessive evaporation at the startreducesthe tempelrature .at that .point and the humidity varies from oneend o f thef line to the; other. Also the weight of the paper in thefesto'on loops places an objectionable strain on the paper at' thefestoon bars, and the bars leave marks en the paper.

j 'I'he object of the invention in general fis to attain the benecialresults of loft drying or festoon drying coupled with the speed,eiliciehcy 'and economy of machine drying. It is well understood thatthe lett drying method produces a strong,

tough-paper with its cockled surface characteristic of high grade paper,due to the fact that the wet paper is allowed to dry in a thoroughlyrelaxed condition wherein its natural shrinkage Y produces 'no strainstending to weaken the 'ber such as occur inthe usual machine driedproduct.

Having this in mind I have devised an apparatus which haridles the' webin a continuous run 'as it comes from the paper making machine, andduring its drying process keeps it traveling without strain or tensionand so that it may be exposed with substantial uniformity-on both sidesto the action of the drying air. At the end of its run when the. paper'is completely dry and may withstand tension without' injury-it may bewound upin a nished roll-or subjected to further nnishing processes asmay bedesired Important features of theinyention to be observed aretirati-the web of paper formed on the paper making machine is deliveredtherefrom in single long runthrough a'conflned and controlled dryingatmosphere and withsufficient initial pro-' pelling force to keepthe webtraveling from 'one end to the other of its run.' A conveyor is providedto support the paper during its run but imparts no pulling tensionthereto, the paper being permitted ,to ride thereon in a thoroughlyrelaxed and unstrained condition. At the dry end of the run atension-barrier is provided whereby the .completely dried web may bepulled along after passing therethrough and which prevents said pullingtension front being transmitted backwardly tothe drying web on theconveyor.

Other and further advantages will be apparent from the followingspeciiicationandclaims.

In the accompanying drawing which illustrates one, embodiment of theinvention; i Fig. 1 is a sideview of a drier unit constructed yaccordingt the invention; f `Fig. 2 is a plan 'view on a larger scale of aportion of the drier structure, parts being broken away; o

Fig. 3 is asection substantially on line -3-3 of Fig. 2; v v

Fig. 4 is a section Fig,f2;'v and Fig. 5 is a fragmentary elevationalview showing an attenuation arrangement of the web supf z, 24,079UNITEDVSTATES' PATEN substantially o n line 4*'-4 of series of dryingcylinders I, an elongated drying chamber 2 provided with a blower 3 andan air conditioning unit 4. The drying cylinders I may be ofusualconstructicn and serve to lower the initial moisture content of thepaper to the point where shrinkage starts to become a. troublesomeactOr. From the cylinders I' the paper web enters the chamber-2, bestshown in Figs. 2, 3 and 4. The chamber 2 is divided lengthwise by a vertical partition 5 into a walkway 6 and a main chamber or tunnel l.Mounted in the tunnel 'I are a plurality of transverse rolls 8 adaptedto support the paper web indicated at I0. The rolls 8 ,are formed ofspaced narrow slats II and are rotatably journaled in partition 5 and awall I2 of the chamber.

are provided with two pulleys Il by means of which each succeeding rollis driven from the preceding roll by belts I5, the initial roll beingdriven from a motor I6 by a belt I1.' The speed of the motor7 isvcontrolled by a control unitindicated at I 8 which may be of .anyconventionalA construction. The surface speed ofrolls 8 ismadc such asto .oat the web forward at the initial speed imparted to it by thecylinders I, so that no drag or strain is placed on the web in its pasesage, through the tunnel and the paper .while The shafts I3 of the rollsextend outwardly beyond the chamber wall I2 anddrying isssubstantiallyas free vfrom restraint is the case in loft drying. In order to'adjlistthe speed of the rolls 8 to accommodate the shrinkage of the webas it dries, means are provided at intervals for `modifying the speed ofthe succeed- -ing' rolls and in the embodiment -shown this isaccomplished by substituting cone pulleys 20 for the-outer pulleys IB oftwo adjacent rolls 8. The

shaft of one of the adjacent pair of rollscarry- 1 ing the cone pulleysis made hollow-to receive a shaft 22 passing through the pulley andhaving its end beyond the pulley screw threaded and journaled in abearing j23^formed on a bracket 25 secured tothe wall I2. A belt shifter26 is threaded on the shaft 22 and engages the belt 2l connecting thecone pulleys. The opposite end of shaft 22 is provided with a handwheel30 acces-.- sible from the walkway 6 by which the belt 28l may beshifted to Iadjust the speed of rolls 8. In order that the attendant mayinspect the traveling web windows 3i are provided at intervals in thetunnel wall. A transverse metal partition is positioned across thetunnel forming with the top of the chamber an air duct 36 spaced-abovethe traveling web. Spaced transverse metal partitions .31 and 38 form asimilar air duct 40 spaced below the traveling web. Partition 38 andtheoor of the chamber form a return duct 4I as later described. Air ducts36 and 40 are closed at their ends adjacent the forward end of thetunnel as indicated respectively at 42 and 43 inFig. 1. Air is forcedinto the 'ducts at a point adjacent their rear ends by a blower 44 ofanysuitable type, driven by a motor 45. As shown in Fig. 3 the blowerdischarges through branch ducts 46 and 41 connecting respectively withducts 36 and 40.

As best shown inl Figs. 3 and 4 the partitions 35 and 31 are providedwith a plurality of apertures 50 formed by making U-shaped cuts in thepartitions, the metal within the cuts being bent outwardly at an angleof substantially 45 to form deilectors 51 extending into the air ductsin the path ofthe air flow and directing the' air into the tunnelagainst the moving web of paper. As shown in Fig. 1 the air passing intothe tunnel `through the aperturesA 50 is discharged at the end of thetunnel into thevreturn duct 4I by which it is returned to the blowerthrough. duct 53. Fresh air is also supplied to the blower through anopening 54 formed in a casing 55 in which is positioned an air Washer56, an air lter 51 and a heater 58, the vlatter being supplied withsteam through a pipe 59 having a valve 60' by means of which thetemperature offthe air may be controlled. If the fresh air entering theair system is very dry the moisture expelled from the paper tends tobring the circulating air to the desired humidity. An air outlet 6lprovided with an exhaust fan 62 and'controlled by a damper 63 permitsdischarge of the moisture ladened air at a rate such that in combinationwith the dry air entering through opening 54 the humidity of the aircirculating in the tunnel may be maintained at the desired humidity asindicated by wet bulbs (not shown) positioned at convenient points inthe tunnel andVv viewable through the windows 3|. p y

lThe paper web is discharged from the tunnel. over a turtle back througha tension control devicel 66 to a power driven wind up 6l` of anysuitable kind, the tension device being adjusted to prevent the wind upfrom exerting drag on the paper web in the tunnel.

It will be seen that the web moves continuously through the tunnelwithoutsubstantial tension and substantially free from restraint as itdries.

The narrow slats I'I ywhich form the surface of the rolls move asYpreviously pointed out at sub stantially the surface speed of the paperand no marking or marring of the surface of the web takes place as itadvances through the tunnel.

In Fig'. 5 is shownan alternative arrangement in which the rolls 8 arenot positively driven but are placed on an incline so that the paperadvances freely by gravity under the initial movement imparted by thecylinders I.

I claim: 1. In an apparatus for drying material in a continuous runningweb, in combination, a substantially straight line drying tunnel, aplurality of drying cylinders positioned at the inlet end of 5 thetunnel between which the web passes and by which the moisture content ofthe web is reduced to a point short of where substantial shrinkageoccurs, said cylinders -advancing the web into the drying tunnel..a webconveyor in the 10 drying tunnel which receives the web from saidvvcylinders, said conveyoncoxnprising a series of slatted open rolls ofrelatively large diameter, the rolls` being spaced apart so thatthetraveling web sags between adjacent rolls and the shape of the 15portion of the web supported by each roll conforms to the curved surfaceof a section of a cylinder formed by passing a plane through-each`cylindrical roll parallel to its longitudinal axis.'

stantially without tension, means for causing currents of air to ow insaid tunnel along both .the upper and lower sides of the traveling web,and means to direct said air currents against3 vthe web, with acomponent of motion inthe direction of web travel, throughout the lengthof the tunnel.

2. In an apparatus for drying material in a continuous running web, incombination, al sub- 35 stantially straight line drying tunnel, aplurality of drying cylinders positioned at the inlet end of the tunnelbetween which the web passes andv by whichthe moisture content` of theweb is re.

duced to a point short of" where .substantial 4K0v shrinkage occurs..said cylinders advancing. the web into the drying tunnel, a webvconveyor in the drying tunnel which receives the web from saidcylinders, said conveyor comprising a series of slatted open rolls ofrelatively large diameter, 45

the rolls being spaced apart so that the traveling web sags betweenadiacent rolls and the shape' A of the portion of the web supported byeach roll conforms to the curved surface of a section of a cylinderformed by passing a planethrough each 5 cylindrical roll parallel toits'longitudinal axis, means extraneous of said web' for, driving thesupporting rolls, other means for 4adjusting the'speed of certain rollswith respect to other rolls so that 55 all the rolls are driven at aspeed regulated to the shrinkage of the web and the initial speedimparted to the web by the drying cylinders whereby the web is advancedthrough the tunnel substantially without tension, partitions placed inthe tunnel to form air ducts above and below -the conveyor, said ductsbeing connected to a being so positioned 'that air currents passingthrough the air ducts are directed onto both sides of the web with acomponent of motion in the direction of travel ofthe web, and adischarge duct for removing the air forced into said tunnel.

WILLIAM WHITING.

